Revert of Add OnDisplayMetricsChanged in DisplayObserver.

ui/message_center/views/message_popup_collection.cc

Index: ui/message_center/views/message_popup_collection.cc
diff --git a/ui/message_center/views/message_popup_collection.cc b/ui/message_center/views/message_popup_collection.cc
index d1116d6f3464c4807448b30f638b2d966f15dac5..4dd70a47128b9b0cefa16addbc37a5c531cfb362 100644
--- a/ui/message_center/views/message_popup_collection.cc
+++ b/ui/message_center/views/message_popup_collection.cc
@@ -561,6 +561,14 @@
   RepositionWidgets();
 }
 
+void MessagePopupCollection::OnDisplayBoundsChanged(
+    const gfx::Display& display) {
+  if (display.id() != display_id_)
+    return;
+
+  SetDisplayInfo(display.work_area(), display.bounds());
+}
+
 void MessagePopupCollection::OnDisplayAdded(const gfx::Display& new_display) {
 }
 
@@ -570,15 +578,6 @@
     display_id_ = display.id();
     SetDisplayInfo(display.work_area(), display.bounds());
   }
-}
-
-void MessagePopupCollection::OnDisplayMetricsChanged(
-    const gfx::Display& display, uint32_t metrics) {
-  if (display.id() != display_id_)
-    return;
-
-  if (metrics & DISPLAY_METRIC_BOUNDS || metrics & DISPLAY_METRIC_WORK_AREA)
-    SetDisplayInfo(display.work_area(), display.bounds());
 }
 
 views::Widget* MessagePopupCollection::GetWidgetForTest(const std::string& id)